Scarlet Witch and Quicksilver's debut into the Marvel Cinematic Universe in Avengers: Age Of Ultron came as a surprise to many Marvel fans, as the film rights were believed by many to be owned by Fox. While this is partially true, Wanda and Pietro Maximoff's history in the main Marvel Comics world (Earth-616) allowed their film rights to be co-shared among Fox and Marvel Studios, as Scarlet Witch and Quicksilver were two of the earliest members of the Avengers.
Another supporting factor was the more recent reveal in Marvel Comics that Quicksilver and Scarlet Witch are, in fact, not Magento's biological children, and they were never mutants at all. As of now, Marvel Studios has the higher branch of power over these specific characters, and Fox may not have them much longer.
This allowed Marvel Studios to write hundreds of different origin stories for the two characters when they debuted into the #MCU. Instead of being mutants, both Wanda and Pietro seemingly got their powers from Loki's Scepter, which contains one of the six Infinity Stones that Thanos needs to gain the full potential of his gauntlet: the Mind Stone.
The Mind Stone was supposedly used by HYDRA to experiment on the twins, granting them their abilities. However, almost three years into the future, some things just don't quite add up the way they used to. More specifically, how Scarlet Witch got her entire set of abilities. My latest MCU theory suggests that Scarlet Witch didn't get her abilities from the Mind Stone, but instead the Reality Stone.
Laying Out The Theory
I know what you are already thinking: The Aether was clearly taken to the Collector's museum after the events of Thor: The Dark World. Yes this is true, but HYDRA wouldn't need the Aether itself in order to transport its power into a being. In Thor: The Dark World Odin described the Aether, saying:
"The Aether is fluid and ever changing. It changes matter into dark matter. It seeks out host bodies, drawing strength from their life-force."
The form of the Aether is non-existent; it isn't one singularity, but instead many forms powered through several hosts throughout the galaxy. Their pure existence powers the Aether and it allows it to exist, but Wanda wouldn't even have to be close to the Aether for her to be infected by its dark matter. Here's how it could happen:
In the eighth episode of Agents Of S.H.I.E.L.D., which takes place immediately after the convergence seen in Thor: TDW, Agent Phil Coulson and his team have to clean up after the huge mess left behind by Thor and Malekith. While on the job the team started to notice that many of the relics and wreckage were stolen. Could these people be the Vulture and his crew from Spider-Man: Homecoming?
It would make sense, as Vulture has been in business since the events of The Avengers, which took place in 2012. It would also make sense that HYDRA would purchase such relics from Vulture in order to get their hands on such powerful entities. HYDRA could have easily known the whereabouts of the relics and who has them as S.H.I.E.L.D. was still infiltrated by HYDRA and wasn't discovered until a year later in Captain America: The Winter Soldier.
How does this relic being sold to HYDRA have anything to do with Scarlet Witch getting her abilities? Well, In Agents Of S.H.I.E.L.D. we also learn that certain alien relics can have traumatic effects after coming into contact with humans, just like the Chitauri Helmet that killed the firemen in Episode 6 of #AgentsOfSHIELD. Back to Episode 8, we see that the Aether can posses a material, and not just lifeforms, as seen with the Asgardian staff that enraged several people, turning them into complete dark matter. All it would take is one Aether-possessed item from the convergence that Wanda Maximoff to come in contact with that changes her life forever.
Another thing to keep in mind are the interesting colors that come with both the twins' abilities. Pietro has more of a resemblance to the Mind Stone with his vibrant blue color when he runs. Wanda has a red mist form when she uses her "psionic" powers, that don't reflect anything characteristic of the Mind Stone.
The scene in Avengers: Age Of Ultron where Wanda gave the Avengers visions of their worst fears, people assumed that this automatically proved that her powers were, in fact, psionic. However, the Reality Stone makes new realities and forces enemies to see the worst things they can imagine. When those angry rioters came in contact with the Asgardian staff possessed by Aether, their worst memories started replaying in their head, similar to what Wanda did to the Avengers.
- A theory written by fellow creator Tom Bacon suggests that the reason why all Infinity Stones are always in close proximity to each other and seem to end up on Earth is caused by a force of magnetism. This theory could be the very reason why Vision and Scarlet Witch have such a strange connection and interest in each other, despite the fact that Vision is a robot. The Mind Stone in Vision's head is causing Scarlet's inner Aether to attract to Vision.
- In Thor: TDW, every time the Aether tried to possess a specific being, the eye color of the host changed. In Avengers: Age Of Ultron and Captain America: Civil War, every time Scarlet Witch began to use her powers her eye color changed to red.
- The energy blasts she uses when fighting are the exact same as the red energy blasts seen in Thor: TDW in a flashback years ago when the Dark Elf leader Malekith used the Aether to attack Asgard.
If this theory is indeed true, Scarlet Witch will most likely play a very dominant role in #InfinityWar, as the effects of the Reality Stone won't be able to stop her. Avengers: Infinity War hits theaters May 4, 2018.